HCS Products for Apoptosis and Cell Viability

Many different approaches are utilized in the study of programmed cell death or apoptosis. Cell death cascades are complex and dynamic, underscoring the importance of a multi-parametric approach to assessment of apoptosis. Understanding the mechanisms of cell death and survival can represent a critical aspect of toxicological profiling and drug discovery. Life Technologies offers a variety of products for developed for multiplex imaging-based detection of key apoptotic markers on high content screening platforms or classic fluorescence microscopy.

Our newest product for detecting apoptosis is the Click-iT® TUNEL Imaging Assays which utilize a dUTP nucleotide modified with an alkyne, a small functional group that enables the nucleotide to be more readily incorporated by TdT than other modified nucleotides. Detection is based on a click reaction between the alkyne and an azide modified dye. Compared to other TUNEL assays, the Click-iT® TUNEL assay is able to detect a higher percentage of apoptotic cells under identical conditions. The assay is also fast and is complete within 2 hours. Furthermore, the Click-iT® TUNEL assay allows multiplexing with surface and intracellular biomarker detection.

Life Technologies offers LIVE/DEAD® Viability and Cytotoxicity kits, an extensive line of reagents and assays for determining cell viability on a wide variety of instrument platforms. The diversity of live cells and their environments makes it impossible to devise a single viability assay applicable to all cell types. Because viability is not easily defined in terms of a single physiological or morphological parameter, it is often desirable to combine several different measures, such as enzymatic activity, membrane permeability, and oxidation–reduction (redox) potential, when determining cell health or drug toxicity. Each assay method has inherent advantages and limitations and may introduce specific biases into the experiment; thus, different applications often call for different approaches.One of the most reliable methods for determining cell death is to use an impermeant dye that can only enter cells and become detectable if the plasma membrane is compromised or degraded.

Our latest addition to these viability kits is the HCS LIVE/DEAD® Green Kit. Validated for HCS platforms, this kit combines HCS NuclearMask™ Deep Red stain to indicate total cell numbers along with Image-iT® DEAD Green™ viability stain for discrimination of dead cells by plasma membrane integrity. Both probes bind to nucleic acids, and, because signals are retained adequately after fixation and permeabilization, this assay may be combined with antibody labeling. Hoechst 33342 is also provided in the kit as an alternate segmentation tool to maximize multiplex options.